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In vivo, multimodal imaging of B cell distribution and response to antibody immunotherapy in mice.

Thorek DL, Tsao PY, Arora V, Zhou L, Eisenberg RA, Tsourkas A - PLoS ONE (2010)

Bottom Line: Cellular imaging of the targeted population in vivo may provide significant insight towards effective therapy and a greater understanding of underlying disease mechanics.These data suggest that in vivo imaging can be used to follow B cell dynamics, but that the labeling method will need to be carefully chosen.SPIO labeling for tracking purposes, generally thought to be benign, appears to interfere with B cell functions and requires further examination.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT

Background: B cell depletion immunotherapy has been successfully employed to treat non-Hodgkin's lymphoma. In recent years, increasing attention has been directed towards also using B-cell depletion therapy as a treatment option in autoimmune disorders. However, it appears that the further development of these approaches will depend on a methodology to determine the relation of B-cell depletion to clinical response and how individual patients should be dosed. Thus far, patients have generally been followed by quantification of peripheral blood B cells, but it is not apparent that this measurement accurately reflects systemic B cell dynamics.

Methodology/principal findings: Cellular imaging of the targeted population in vivo may provide significant insight towards effective therapy and a greater understanding of underlying disease mechanics. Superparamagnetic iron oxide (SPIO) nanoparticles in concert with near infrared (NIR) fluorescent dyes were used to label and track primary C57BL/6 B cells. Following antibody mediated B cell depletion (anti-CD79), NIR-only labeled cells were expeditiously cleared from the circulation and spleen. Interestingly, B cells labeled with both SPIO and NIR were not depleted in the spleen.

Conclusions/significance: Whole body fluorescent tracking of B cells enabled noninvasive, longitudinal imaging of both the distribution and subsequent depletion of B lymphocytes in the spleen. Quantification of depletion revealed a greater than 40% decrease in splenic fluorescent signal-to-background ratio in antibody treated versus control mice. These data suggest that in vivo imaging can be used to follow B cell dynamics, but that the labeling method will need to be carefully chosen. SPIO labeling for tracking purposes, generally thought to be benign, appears to interfere with B cell functions and requires further examination.

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Related in: MedlinePlus

Labeling of B cells with fluorescent and MR tracers and evaluation of cellular response.A, SPIO nanoparticles function as MR contrast agents and consist of dextran-coated iron oxide. The dextran has been aminated and labeled with the dye Alexa 680. B, In addition to SPIO, GFP-expressing B cells are also labeled with the membrane intercalating near infrared dye CellVue NIR815 (NIR815). C, Loading of B cells with SPIO (Alexa 680) and NIR815 was confirmed by fluorescence microscopy (40×). D, SPIO loading did not cause any detectable change in the expression of CD40, CD86, CD80, or MHC II. PMA treated B cells were used as a positive control. E, B cells that were loaded with SPIO could still be activated upon the addition of LPS. F, The contrast labeled cells (20×106) were tail vein injected into C57BL/6 mice on day 0. B cell trafficking and distribution was monitored by MR and optical imaging techniques at the indicated time points. Treatment of either PBS or anti-CD79 was administered following the imaging session on day 1.
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pone-0010655-g001: Labeling of B cells with fluorescent and MR tracers and evaluation of cellular response.A, SPIO nanoparticles function as MR contrast agents and consist of dextran-coated iron oxide. The dextran has been aminated and labeled with the dye Alexa 680. B, In addition to SPIO, GFP-expressing B cells are also labeled with the membrane intercalating near infrared dye CellVue NIR815 (NIR815). C, Loading of B cells with SPIO (Alexa 680) and NIR815 was confirmed by fluorescence microscopy (40×). D, SPIO loading did not cause any detectable change in the expression of CD40, CD86, CD80, or MHC II. PMA treated B cells were used as a positive control. E, B cells that were loaded with SPIO could still be activated upon the addition of LPS. F, The contrast labeled cells (20×106) were tail vein injected into C57BL/6 mice on day 0. B cell trafficking and distribution was monitored by MR and optical imaging techniques at the indicated time points. Treatment of either PBS or anti-CD79 was administered following the imaging session on day 1.

Mentions: The loading of B cells harvested from the spleens of C57BL/6 mice was performed using a cationic 53.5 nm diameter SPIO nanoparticle, schematically illustrated in Figure 1A, through a previously validated procedure [34]. Cells were also labeled with a lipophilic membrane associating dye, CellVue NIR 815 (NIR815), to enable deep tissue fluorescent imaging (Fig. 1B). The proficient loading of the cells was confirmed by fluorescent microscopy, Fig. 1C. B cells from GFP-transgenic mice were employed in order to identify injected cells histologically upon conclusion of in vivo imaging.


In vivo, multimodal imaging of B cell distribution and response to antibody immunotherapy in mice.

Thorek DL, Tsao PY, Arora V, Zhou L, Eisenberg RA, Tsourkas A - PLoS ONE (2010)

Labeling of B cells with fluorescent and MR tracers and evaluation of cellular response.A, SPIO nanoparticles function as MR contrast agents and consist of dextran-coated iron oxide. The dextran has been aminated and labeled with the dye Alexa 680. B, In addition to SPIO, GFP-expressing B cells are also labeled with the membrane intercalating near infrared dye CellVue NIR815 (NIR815). C, Loading of B cells with SPIO (Alexa 680) and NIR815 was confirmed by fluorescence microscopy (40×). D, SPIO loading did not cause any detectable change in the expression of CD40, CD86, CD80, or MHC II. PMA treated B cells were used as a positive control. E, B cells that were loaded with SPIO could still be activated upon the addition of LPS. F, The contrast labeled cells (20×106) were tail vein injected into C57BL/6 mice on day 0. B cell trafficking and distribution was monitored by MR and optical imaging techniques at the indicated time points. Treatment of either PBS or anti-CD79 was administered following the imaging session on day 1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2871797&req=5

pone-0010655-g001: Labeling of B cells with fluorescent and MR tracers and evaluation of cellular response.A, SPIO nanoparticles function as MR contrast agents and consist of dextran-coated iron oxide. The dextran has been aminated and labeled with the dye Alexa 680. B, In addition to SPIO, GFP-expressing B cells are also labeled with the membrane intercalating near infrared dye CellVue NIR815 (NIR815). C, Loading of B cells with SPIO (Alexa 680) and NIR815 was confirmed by fluorescence microscopy (40×). D, SPIO loading did not cause any detectable change in the expression of CD40, CD86, CD80, or MHC II. PMA treated B cells were used as a positive control. E, B cells that were loaded with SPIO could still be activated upon the addition of LPS. F, The contrast labeled cells (20×106) were tail vein injected into C57BL/6 mice on day 0. B cell trafficking and distribution was monitored by MR and optical imaging techniques at the indicated time points. Treatment of either PBS or anti-CD79 was administered following the imaging session on day 1.
Mentions: The loading of B cells harvested from the spleens of C57BL/6 mice was performed using a cationic 53.5 nm diameter SPIO nanoparticle, schematically illustrated in Figure 1A, through a previously validated procedure [34]. Cells were also labeled with a lipophilic membrane associating dye, CellVue NIR 815 (NIR815), to enable deep tissue fluorescent imaging (Fig. 1B). The proficient loading of the cells was confirmed by fluorescent microscopy, Fig. 1C. B cells from GFP-transgenic mice were employed in order to identify injected cells histologically upon conclusion of in vivo imaging.

Bottom Line: Cellular imaging of the targeted population in vivo may provide significant insight towards effective therapy and a greater understanding of underlying disease mechanics.These data suggest that in vivo imaging can be used to follow B cell dynamics, but that the labeling method will need to be carefully chosen.SPIO labeling for tracking purposes, generally thought to be benign, appears to interfere with B cell functions and requires further examination.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT

Background: B cell depletion immunotherapy has been successfully employed to treat non-Hodgkin's lymphoma. In recent years, increasing attention has been directed towards also using B-cell depletion therapy as a treatment option in autoimmune disorders. However, it appears that the further development of these approaches will depend on a methodology to determine the relation of B-cell depletion to clinical response and how individual patients should be dosed. Thus far, patients have generally been followed by quantification of peripheral blood B cells, but it is not apparent that this measurement accurately reflects systemic B cell dynamics.

Methodology/principal findings: Cellular imaging of the targeted population in vivo may provide significant insight towards effective therapy and a greater understanding of underlying disease mechanics. Superparamagnetic iron oxide (SPIO) nanoparticles in concert with near infrared (NIR) fluorescent dyes were used to label and track primary C57BL/6 B cells. Following antibody mediated B cell depletion (anti-CD79), NIR-only labeled cells were expeditiously cleared from the circulation and spleen. Interestingly, B cells labeled with both SPIO and NIR were not depleted in the spleen.

Conclusions/significance: Whole body fluorescent tracking of B cells enabled noninvasive, longitudinal imaging of both the distribution and subsequent depletion of B lymphocytes in the spleen. Quantification of depletion revealed a greater than 40% decrease in splenic fluorescent signal-to-background ratio in antibody treated versus control mice. These data suggest that in vivo imaging can be used to follow B cell dynamics, but that the labeling method will need to be carefully chosen. SPIO labeling for tracking purposes, generally thought to be benign, appears to interfere with B cell functions and requires further examination.

Show MeSH
Related in: MedlinePlus